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Am I right thinking this isnt blackspot?

Posted by curdle 9b (My Page) on
Mon, Aug 19, 13 at 3:23

The holes in the leaves lead me to think this isnt just blackspot...
These are a couple of the more badly affected leaves from my new just breaking into growth bought as a grafted bareroot Mr Lincoln. Its been awfully wet here, and temperatures havent really got past 18 C yet (currently about 14 C) A few of the older plants do have a bit of blackspot on last years leaves, but all the new ones are so far just looking green and healthy, barring the odd aphid.
Except for Mr Lincoln....

Follow-Up Postings:

RE: Am I right thinking this isnt blackspot?

My vote is for blackspot, based on the splotches on the other leaves. If not, it may be burning?

RE: Am I right thinking this isnt blackspot?

Thanks Josh, but I dont think it would be burning.. havent sprayed, or fertilized anything anywhere in the garden yet; and as far as I know, none of the neighbours have none of Mr L's fellow pot ghetto mates are showing any leaves like this.
Its still the last month of winter here, so we are only getting a bit of blue sky every now and again to lift the grey, no where near enough to burn anything.

hmm..blackspot I can deal with, I just wasn't sure about the holey bits and got worried it might be something or some bug I wasn't familiar with..

RE: Am I right thinking this isnt blackspot?

The holes could be from rose slugs.

RE: Am I right thinking this isnt blackspot?

I would think much of Zone 9 would be too hot for rose slugs this time of year. It definitely looks fungal, whether it's actual black spot or some other fungal leaf spotting (there are a couple of others which mimic black spot). The holes may simply be where prickles have poked holes through the tissues or the dead area has fallen out. They don't appear to be slug damage to me. Kim

RE: Am I right thinking this isnt blackspot?

  • Posted by curdle 9b, Australia (My Page) on
    Mon, Aug 19, 13 at 8:44

Thanks KIm and Buford :)
Its not hot at all here yet. My seasons are all back to front from most of the posters here. I just worked out I could update my Zone to mention country- for some reason I thought you could only fit zone in.
I am pretty new to the rose thing, but the obsession seems to be taking hold. I started with one or two (ok 5, no, 7... what can I say, its a long growing season here ) container plants last year...this year ordered quite a few more bareroots, which got planted about a month ago, Mr Lincoln is one of those).

Now you have me worried that sawflies are something I can look forward to! As if green loopers on the vegies aren't bad enough!..

Although on the upside, there should be plenty of new rose pics over the next few months..

This post was edited by curdle on Mon, Aug 19, 13 at 8:47

RE: Am I right thinking this isnt blackspot?

What is looks like to me is cercospora with possibly a small helping of blackspot. The holes are a dead ringer for cercospora, though. A lot of the blackspot fungicides work on cercospora, but not all. I'm not really up on those things.

RE: Am I right thinking this isnt blackspot?

You have cercospora, spot anthracnose, and powdery mildew (just beginning). We call it the midsummer trifecta because that's when they often show up around here, but it can happen at other times. You might have a little black spot too.

You can see the beginning of powdery mildew by the curly leaves.

Cercospora and spot anthracnose often show up simultaneously because their conditions for growth are essentially the same. Around here, we tend to look for them following a midsummer heat wave. . YMMV

Generally, the standard rose fungicides that you use for black spot are also labeled for anthracnose and cercospora . So if you are spraying your fungicides on a schedule, you shouldn't see much of them. Those fungicides will usually take care of your PM as well

This post was edited by nickl on Mon, Aug 19, 13 at 10:11

RE: Am I right thinking this isnt blackspot?

I agree with Nicki's diagnosis. If the gray centers drop out leaving holes, that indicates spot anthracnose rather than cercospora, but I can't make that out in the picture.
The raggedy dark spot in upper left might be blackspot.

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